Fish Surveys

Published

April 16, 2024

Metadata

Figure 1: Location of fish surveys
Table 1: Summary of work by island and exposure
Number of fish surveys per location, habitat, and exposure
Exposure Strata # Sites # Transects # Reels Surveyed distance (m)
Fanna
Forereef Leeward 2 1 2 6 150
Forereef Windward 2 5 10 30 750
Total — — 6 12 36 900
Helen
Backreef Lagoon 1 1 2 6 150
Patchreef Lagoon 2 3 6 18 450
Forereef Leeward 2 6 12 36 900
Forereef Windward 2 5 10 30 750
Total — — 15 30 90 2250
Merir
Forereef Leeward 2 3 6 18 450
Forereef Windward 2 4 8 24 600
Total — — 7 14 42 1050
Pulo Anna
Forereef Leeward 2 2 4 12 300
Forereef Windward 2 2 4 12 300
Total — — 4 8 24 600
Sonsorol
Forereef Leeward 2 4 8 24 600
Forereef Windward 2 3 6 18 450
Total — — 7 14 42 1050
Tobi
Forereef Leeward 2 5 10 30 750
Forereef Windward 2 1 2 6 150
Total — — 6 12 36 900
Grand total — — 45 90 270 6750

QA/QC

Taxa

Pointblank Validation
Validate taxa list

tibble fish_lutWARN 1 STOP — NOTIFY —
STEP COLUMNS VALUES TBL EVAL UNITS PASS FAIL W S N EXT

1
rows_complete
 rows_complete()

▮taxon_code, ▮taxon_valid_name, ▮max_length_tl, ▮a, ▮b, ▮common_family, ▮consumer, ▮trophic, ▮trophic_detailed

 — ✓ 413 355
0.85956		 58
0.14044		 ● — —

2
rows_distinct
 rows_distinct()

▮taxon_code

 — ✓ 413 413
1		 0
0		 ○ — — —
2024-04-16 12:45:06 -05 < 1 s 2024-04-16 12:45:06 -05

Observations

Pointblank Validation
Validate observations

tibble mutate(fish_obs, diff = (avg_tl_cm - max_length_tl)/max_length_tl)WARN 1 STOP — NOTIFY —
STEP COLUMNS VALUES TBL EVAL UNITS PASS FAIL W S N EXT

1
col_vals_not_null
 col_vals_not_null()

▮taxon_code

 — ✓ 11781 11781
1		 0
0		 ○ — — —

2
col_vals_not_null
 col_vals_not_null()

▮n_ind

 — ✓ 11781 11779
0.99		 2
0.01		 ● — —

3
col_vals_not_null
 col_vals_not_null()

▮min_tl_cm

 — ✓ 11781 11780
0.99		 1
0.01		 ● — —

4
col_vals_not_null
 col_vals_not_null()

▮max_tl_cm

 — ✓ 11781 11780
0.99		 1
0.01		 ● — —

5
col_vals_gte
 col_vals_gte()

▮max_tl_cm

▮min_tl_cm

 ✓ 11781 11769
0.99		 12
0.01		 ● — —

6
col_vals_lte
 col_vals_lte()

▮diff

0.1

 ✓ 11781 11579
0.98285		 202
0.01715		 ● — —
2024-04-16 12:45:12 -05 < 1 s 2024-04-16 12:45:12 -05

Location summary

Table 2: Summary of results by island and depth strata.
Average species richness, abundance, and biomass by location
Sites # Transects # Reels # Taxa Abundance (ind/m2) Biomass (g/m2)
Fanna
Deep 6 6 18 77.50 13.76 751.78
Shallow 6 6 18 60.83 14.36 328.57
Overall — 12 36 69 14 540
Helen
Deep 14 15 45 67.53 6.82 695.77
Shallow 14 15 45 74.87 9.74 644.20
Overall — 30 90 71 8 670
Merir
Deep 7 7 21 67.57 6.33 875.68
Shallow 7 7 21 73.29 5.68 696.30
Overall — 14 42 70 6 786
Pulo Anna
Deep 4 4 12 61.25 17.72 1431.37
Shallow 4 4 12 67.50 10.43 756.46
Overall — 8 24 64 14 1094
Sonsorol
Deep 7 7 21 72.43 17.38 552.97
Shallow 7 7 21 64.00 17.17 439.10
Overall — 14 42 68 17 496
Tobi
Deep 6 6 18 69.50 7.87 875.67
Shallow 6 6 18 73.00 13.96 670.89
Overall — 12 36 71 11 773

Analyses

Diversity

Figure 2: Number of species by order and family
Figure 3: Species richnnes by island
Table 3: Results of Adonis model for univariate analysis of fish species richness
Results of Adonis model for univariate analysis of fish species richness
df SumOfSqs R2 statistic p.value
depth_strata 1 19.699 0.002 0.155 0.677
location 5 690.066 0.060 1.086 0.347
exposure 1 859.704 0.075 6.763 0.006
habitat 1 15.851 0.001 0.125 0.731
diver 1 16.078 0.001 0.126 0.718
Residual 79 10042.063 0.876 NA NA
Total 89 11463.122 1.000 NA NA
Figure 4: Species richnnes by exposure by island

Abundance

Figure 5: Fish abundance by island
Table 4: Results of Adonis model for univariate analysis of fish abundance
Results of Adonis model for univariate analysis of fish abundance
df SumOfSqs R2 statistic p.value
depth_strata 1 29.142 0.006 0.764 0.383
location 5 1239.975 0.235 6.498 0.001
exposure 1 227.512 0.043 5.961 0.014
habitat 1 2.027 0.000 0.053 0.819
diver 1 698.274 0.132 18.295 0.001
Residual 79 3015.233 0.571 NA NA
Total 89 5280.135 1.000 NA NA
Figure 6: Abundance by exposure by diver
Figure 7: Abundance by exposure by island

Biomass

Figure 8: Fish biomass (g/m2) by island
Table 5: Results of Adonis model for univariate analysis of fish biomass
Results of Adonis model for univariate analysis of fish biomass
df SumOfSqs R2 statistic p.value
diver 1 262324.43 0.014 1.875 0.182
depth_strata 1 951567.86 0.051 6.800 0.014
habitat 1 16203.53 0.001 0.116 0.701
exposure 1 1621950.14 0.087 11.590 0.002
location 5 3180460.38 0.170 4.545 0.002
Residual 79 11055315.90 0.590 NA NA
Total 89 18742487.34 1.000 NA NA

By depth

Figure 9: Biomass by depth strata by island

By exposure

Figure 10: Biomass by exposure by island
Table 6: Summary of results by island and exposure
Average species richness, abundance, and biomass by location and exposure
Sites # Transects # Reels # Taxa Abundance (ind/m2) Biomass (g/m2)
Fanna
Leeward 1 2 6 69.50 10.40 812.14
Windward 5 10 30 69.10 14.79 485.78
Helen
Lagoon 4 8 24 67.50 8.04 190.96
Leeward 6 12 36 66.42 6.02 543.27
Windward 5 10 30 79.90 11.18 1205.28
Merir
Leeward 3 6 18 68.17 5.40 867.84
Windward 4 8 24 72.12 6.46 724.61
Pulo Anna
Leeward 2 4 12 62.00 13.51 667.86
Windward 2 4 12 66.75 14.64 1519.97
Sonsorol
Leeward 4 8 24 65.38 13.97 398.98
Windward 3 6 18 72.00 21.68 625.45
Tobi
Leeward 5 10 30 70.80 11.36 743.97
Windward 1 2 6 73.50 8.67 919.82

By family

Figure 11: Biomass by family
Figure 12: Biomass by family and depth strata

By trophic group

Figure 13: Biomass by trophic group

By species

Figure 14: Frequency, abundance, and biomass by species

Community assemblages

Table 7: Fish assemblages Adonis model
Results of community composition Adonis model
term df SumOfSqs R2 statistic p.value
location 5 5.168 0.170 3.820 0.001
exposure 1 0.359 0.012 1.325 0.129
habitat 1 0.404 0.013 1.493 0.046
depth_strata 1 0.809 0.027 2.990 0.001
Residual 80 21.648 0.713 NA NA
Total 89 30.375 1.000 NA NA
Figure 15: Principal coordinates analysis
Table 8: Results of ANOVA on the ordination model
Significance of each term in the ordination model
term df SumOfSqs statistic p.value
location 5 6.231 2.860 0.001
exposure 2 2.446 2.807 0.001
depth_strata 1 0.968 2.220 0.001
habitat 1 0.569 1.306 0.064
Residual 80 34.863 NA NA